If I'm not mistaken, VHS film makes a pretty good binder for tying things. Other than that...let's see. You could half a VHS casing and use a half as an ashtray...You can use it to store things in...you can use the film for arts and crafts, or (I don't personally know how this would turn out) make something like a black light disco ball? A quick google search brought up a few ideas...I rather like the bookend idea in this link...
http://www.craftstylish.com/item/436...tapes/page/all
As for cassette tapes...Man be careful which ones you use, you might be ruining a classic you won't be able to find on CD...my dad has some old time pentecostal camp meeting music he lost, can't find it anywhere on CD.