Games to learn some irregular verbs:
Practise here and here
If you want more...click on the following links:
http://www.adelescorner.org/grammar/past_tense/past_regular.HTML
http://www.bradleys-english-school.com/online/speedword/spdwrdpast1.html
http://www.adelescorner.org/grammar/past_tense/past_tense_negative.HTML
Have fun!