I just finished running my BRP superheroes-in-prison one-shot game called SuperMax, which boils down to my take on The Authority meets OZ by way of The Boys. I went overboard creating a faux-Wikipedia as setting background and didn't put as much effort into constructing the plot, but it was refreshing to play it by ear, and the players seemed to have a really fun time. The best moments came from the Superhung character, from Fedayeen getting his leg caught in his urethra as Superhung created a "penis elevator" for everyone to ride down the ventilation shaft to freedom, to Superhung dealing the killing blow by stretching out his penis to launch himself through The Redeemer's chest, with the Jesus-Freak Superman sliding lifelessly down his member. About my only regret was that I didn't get a chance to work in my Wolverine/Punisher/alcoholic Boston sports fan character Boston Crab, because the PC's found a way to escape early on.
While the game was insane, BRP leaves much to be desired as a system. The way the effects of powers are handled requires a lot of math, stripping away the best quality of the BRP system (its quick simplicity) and leaving all its vices (too easy failure). I mitigated this by including "Luck Points", poker chips that could be spent to re-roll, flip rolls (turn an 81 into an 18), and other stuff that made the characters significantly more competent. Still, I had to fiddle with almost everyone's powers during chargen, and handwave a lot of effects to keep things moving. Spirit of the Century would've worked much better, but I wanted to go with a system I knew when running a setting I'd created wholly on my own.