Typing.com http://www.typing.com/ provides straightforward keyboarding practice without a lot of bells and whistles. Students in the Rahm, Arabia, Mattaliano, Scott, Warley, and North classes already have class accounts. Anyone can sign up for a free account.

If you're looking for a change of pace, try one of the following:

BBC Dancemat typing practice http://www.bbc.co.uk/guides/z3c6tfr#zgkpn39 provides game-like typing practice

TypeTastic https://typetastic.com/ is another game-like site that reviews the basic keyboard key positions