We're still discovering the many ways Apple has celebrated the Mac’s 30th anniversary. The multi-faceted festivities include a prominent section on Apple's homepage providing a visual timeline of all Mac models since 1984, a nice ‘Happy Birthday, Mac’ section on the Mac App Store highlighting apps and games that capture the spirit of what makes the Mac a Mac, aptly-themed Apple Store window displays and commemorative posters at Apple's HQ listing all former and current Apple employees, to name a few (bonus: MacWorld and ABC interviews).
This one tidbit comes from iOS developer Greg Barbosa who discovered a charming font on Apple's servers which contains pictograms of various Mac models. I suggest installing the font ASAP as Apple could pull it at a moment's notice...