Android tablets bar the Nexus 7 may be waiting on Jelly Bean, but that hasn't stopped the HP TouchPad from grabbing Android 4.1 already. HP's webOS tablet failed to set the world alight prior to its sudden discontinuation last year, but regular Android ports (and an alluring $99 sticker price to clear stock) have given it a second lease of life.
This particular Jelly Bean install on the TouchPad is an unofficial port of CyanogenMod 10 by Jcsullins, though it's very early days and there are still plenty of gaps in functionality. Although things look reasonably smooth in Liliputing's video below, the to-do list is plenty long.
Hardware video and graphics acceleration aren't functional, and neither is audio. The front-facing camera doesn't work, and neither does the microphone. In short, if you're hoping for some (silent) web browsing and email from your Jelly Bean slate, the TouchPad port should suit; everyone else might want to wait until that list gets pared back.
Installation is reasonably straightforward, with instructions here and here, though it's worth noting that some TouchPad owners are reporting issues with recharging while running the new ROM. That's not universal, however, so you may find you get on fine.