The gang has a site, www.rifftrax.com, to sell recorded riffs to play along with a variety of contemporary movies.
I know of it an and actually watched some...they actually riff on good movies like the Empire Strikes Back, etc.
there is currently a ‘Rift’ between 2 factions of MST3K
Rifftrax and Cinematic Titanic.
both are good. but I prefer they be on a scheduled channel and not on line....