If you subscribe to Hulu, you can once again watch Mythbusters via streaming. However, you can't watch all episodes. Hulu only has the latest two seasons, seasons 13 and 14. But two seasons of Mythbusters is better than none!
If you've never seen Mythbusters, check it out! My daughters love watching it and for the most part the show is kid friendly. Every once in awhile there's an episode we skip. For example, there was an episode on decapitation that I didn't think my daughter was ready for at the time. Use your best judgement as a parent, but most episodes are perfectly fine for an elementary aged child.