I once spent a few very silly hours with Steve Rayhawk coming up with 'autothexis': poor archaic Greek for 'self-sharpening'. I like it because you can use it to talk about self-improvement in Seed AI as well as in your own life. Now it's my email address and profile name on various sites. Also, autothectize, autothectic, and my favorite because 'intelligence explosion' is unwiedly, 'thectodammerung'. ;)

Unfortunately, there seems to be no easy way to say 'self-improvement' in English. I thought about this for a few minutes once and found it moderately disturbing.