On Chanukah we read what may be the most boring part of the Torah: the list of the twelve princes and the gifts they presented at the dedication of the Mishkan (Bamidbar 7). Though all twelve princes give exactly the same gift, the exact description of the gift is repeated almost verbatim for each of the twelve. Describing each gift takes more than 150 words (in my English translation) - so the overall passage comes out to 89 verses and more than 1900 words, with about 1600 of those words being exact repetitions of what was previously stated. Unless you have an an extremely good baal koreh, it's almost impossible to pay attention to the whole thing.
Hoping to explain why the repetition is necessary, I dredged my memory and came up with recollections from my college graduation, which took place 1.5 years ago. My college included about 10 different "schools" for different subjects, which wore different-colored skirt-thingies at graduation and, in some technical sense, graduated separately. As a result, the "formal" part of graduation took quite some time to finish. Here's my best recollection of what the university president said during that part of the ceremony.
"My greetings to the students of the School of Arts and Sciences. [One or two cheesy lines which I don't remember.] I hereby ordain you as graduates of the University of ************, and confer upon you all the rights and privileges which that status entails." (Cheering)
"My greetings to the students of the School of Business. [A different one or two cheesy lines which I don't remember.] I hereby ordain you as graduates of the University of ************, and confer upon you all the rights and privileges which that status entails." (Cheering)
And after that:
"My greetings to the students of the School of Engineering and Applied Science. [More cheesy lines which I don't remember.] I hereby ordain you as graduates of the University of ************, and confer upon you all the rights and privileges which that status entails." (Cheering)
And so on and so on, until the graduates of each of the ten or so schools had their status conferred upon them. (By the way, I have yet to see any rights or privileges as a result of graduation. Except for the right to receive fundraising emails and the privilege of trying to recover financially from $160000 in tuition bills. Thank God for the right and privilege of having my parents.)
Why didn't the university president simply lump all the statements together? As in: "Hey Business, Engineering, Nursing, Med School, Dentistry, and Arts and Crafts students - you guys are all graduated now. Now go home and get drunk. But pleeeaase, don't forget to finish your incomplete Jewish Studies papers, I'm begging you!" That would have saved her at least ten minutes which could have been productively spent looking for suicide bombers to take pictures with.
Well, it was important not only that we all received degrees, but that it was publicly and formally announced that we had received them, from the president specifically. And part of being a formal announcement means that you go over the details unnecessarily. One one hand, these were "magic words" which (like signatures on legal documents and the diploma itself) cause a change in status without any physical action, but only if the correct formula is recited. On the other hand, the very fact that they were said in an abnormal manner emphasized that this was not just another lecture or pep rally, but was instead an extraordinary event with extraordinary meaning.
I think both explanations apply to the dedication of the Mishkan, which like graduation was a formal ceremony to commemorate a change in status. First of all, the dedication was a very unusual event, and describing it in a different style makes clear that it was unusual. Secondly, the gifts of the princes were qualitatively different from other gifts to the Mishkan - from the "terumah" used to build it, and from the "hekdesh" and voluntary sacrifices contributed after it began functioning. Instead, I think the gifts served to connect each tribe to the Mishkan. The Mishkan was not meant to be a disembodied shrine, but rather a means by which God would dwell amongst Israel. In order for this to occur, each tribe of Israel had to individually and formally connect to the Mishkan through a gift. (This may be the deeper meaning of the midrash that each prince's gift was different from the others.) The point of the gift was not the "bottom line", the weight of gold or number of animals, which could be summarized. Rather, the important thing was the gesture that a gift was given, and summarizing the gift would impair the gesture.
A third possible reason for the repetition is to increase our tension and anticipation as we get to the climactic last verse-and-a-half of the chapter: "...This is the dedication of the altar after its anointing. And when Moshe entered the Tent of Meeting to speak with [God], he heard the voice speak to him from above the cover of the ark of testimony, between the two keruvim - and he/it spoke to it/him." Finally, after all the delay, the the Mishkan is complete and God can communicate with Israel (and/or vice versa, depending how you translate the last phrase). This is a historic moment in Jewish history, and by reading a very long "lead-up" to it, we anticipate it and hopefully realize its importance when it comes.