There are many variants of ExtremeProgramming out there.
Without commenting on whether any of them are worthwhile, here are some:
- ExtremeProgrammingForOne
- AlmostExtremeProgramming
- CrystalClearMethodology
- DeveloperOnlyXp
- ExtremeUnifiedProcess
- XpLite (see also XpLiteConsideredHarmful)
- XpJr
- CategoryAdoptingXp
- ExtremeDevelopment--its about the Programmer!
- IndustrialExtremeProgramming
(Add more, please. Some one-line differentiating descriptions would also be helpful.)