most games that are based on a movie aren't that great. i have barnyard & i've actually enjoyed it here & there. they also have a disney princess game available, if you have a girl/girls.
as far as other games i'm not too sure. but like i said mario games are pretty enjoyable. mario party 8, super mario galaxy... super paper mario would be too much reading for them. i don't have it by they might enjoy mario & sonic olympics.
your best bet would be to look on websites for ratings and what not. i always use www.gamespot.com for ratings and reviews [im not trying to advertise lol]