I don't want to appear like one of those guys on most forums that come along after anything happens and say they had already thought about it or done it, but for mothers day this year (first poster went to my mum
) I created a Mosaic of our team logo. At our team social, all team members autographed it and the mosaic is currently framed and hanging in our Engineering classroom. It consists of 2,000+ team photos from 2005 and 2006. Below is a thumbnail that links to the full size (7.93 MB, 2762x2340) mosaic.
I used a freeware program named
AndreaMosaic. It is slightly confusing to use, so I recommend following their tutorial if you wish to create a mosaic.
Poster-sized mosaics of team's logos (using photos from that particular build season), at least in our team, can be a huge hit, and often a great source of donations!
EDIT: Almost forgot to mention, but using this software on a 3 GHz Dell with 2 GB of RAM took less than an hour... but it took multiple tries for the optimal look (there was a single solid white photo somewhere in the source files that took me forever to find and was screwing up all of the mosaics)! Also note that this software is extremely flexible and has options for how much to alter the photos, how many times to use each photo (for small collections), and how close to the other copy to repeat.