Because it's TMNT, before the third movie ruined the franchise. And no, in my opinion, having Vanilla Ice on screen for two minutes doesn't taint the movie, as everyone claims it does.
https://www.youtube.com/watch?v=mzAcBuwM2b0Because it's the best video game movie ever made ... although that's not saying much.
https://www.youtube.com/watch?v=vndPpCk_4D8Because Raul Julia!
https://www.youtube.com/watch?v=Ssn2GGNVF0wBecause bellybuttons (although the girls all covered up for the third act, sadly).
https://www.youtube.com/watch?v=_SEJhU0e2mM