In the same autodidactic vein as blankful, here's a non-boring typing tutor/test that I threw together for my own amusement.
http://typealong.com/
Remaining todos:
1) support umlauts and other non-ascii charcters so I can practice my Deutsch
2) make keyboard display into a heatmap showing error hotspots
3) show full keyboard and not just letters.
4) minor cosmetic stuff, centering, etc.
Hope someone else finds this useful!
Reinhard