When it comes to closed guard sweeps, I am a big fan of the Flower Sweep. There are just so many things you can do from it that it makes it a strong attack series to begin with. Arm bars, triangle chokes, omo platas, leg locks, transition to the pit, and that is just getting started.
Recently I discovered this neat little trick playing around with it that can increase your odds of finishing a flower sweep dramatically. If you studied the 10th Planet System of Jiu Jitsu from Eddie Bravo, then you may be familiar with what he calls the Old School Sweep.
This trick uses the same principle to finish a flower sweep if your opponent stuffs your first attempt (or if you goofed up), and can be used in one of two ways. Watch the video and let me know your thoughts.