Entire neighborhoods of Sims are being mysteriously graced with eternal youth, while some characters are finding all their needs fulfilled by a single shot of magic espresso. Others no longer need to empty the toilet after potty training their toddler. Some Sims are being abducted by aliens when they glance through their telescope -- every time, instead of just occasionally, which is normal.

All this mayhem is the work of a community of experimenters wielding hex editors, custom programs and reverse-engineering skills who began mastering their own Sims 2 worlds immediately after the game's release last September. The hackers share their weird science with one another through public websites and forums.