I find typing an entire sentence with my eyes closed is one of the best ways to develop good typing skills. It's really weird feeling myself correcting typos before I can svn see them. It also penalizes errors a lot more, and thus encourages a "get it right the first time" style of typing, instead of my usual "make mistakes and fix them" style.

(Typed the preceding paragraph blind. "svn" is a typo for "even", and I was only aware I screwed it up ^^)

It's also a fun "party trick" - I like to creep out co-workers by turning to listen to them and continuing to type :)