Lately, I've become a big fan of the simple online mixtape creation tool Muxtape. I've always loved creating mixtapes for friends and this tool was the best solution out there; recently, it became so popular that several tools like Muxtape Stumbler have been built around it.
Unfortunately, I doubt we'll be having much more fun with Muxtape in the future, as the site now sports only the following message:
Muxtape will be unavailable for a brief period while we sort out a problem with the RIAA.
It sounds optimistic, but things rarely turn out that way. Muxtape will probably argue that they cannot control if their users have rights to upload music to the service, but let's face it, basically no one except the record companies have the right to upload 99.9% of any available music anywhere, and RIAA will simply point that out.