Castles & Creatures is FIST vs DnD.
The PDF is 2 pages, with a beautiful and very appropriate feeling high contrast layout. It's easy to read---even with slightly small text---and every bit of it pops off of the page in a good way.
Contents-wise, C&C is a good shotgun or oneshot scenario, and an excellent introduction to FIST overall.
The scenario is straightforward but flavorful, with technicolor fantasy elements intruding on small town americana. The fights feel appropriately balanced, and there's even multiple routes through the content, with branching endings as well.
Overall, if you want to indulge in some Stranger Things style retro fun in your FIST game, or if you just want a good, solid module for a oneshot, C&C is a great pick.