Dweezil Zappa is selling a bunch of t-shirts on his Rewardmusic platform.
When you buy a t-shirt, you receive a bonus song.
All of the songs have also been made available as a new release, the "T-Shirt Songs" collection.
It includes two tracks that were written by Dweezil (and previously released on his "Archival Tracks" collection). The thirteen other pieces are (excellent) live recordings from the ZappaPlaysZappa tours.