Interactive verb practice http://www.english-forum.com/00/interactive/iverbs/
Flashcard game http://www.englishbytes.net/irreg1.html
Quiz http://www.englishclub.com/grammar/verb-tenses_past_quiz.htm
Two player game http://www.quia.com/cb/8111.html
Interactive Internet quiz http://www.manythings.org/c/r.cgi/quiz
Flash games! http://www.manythings.org/qs/verbs.html