One Ball, Two Ball with a dash of Rush N Crush. You will need at least 4 players, two teams of two. They should be able to rally from the baseline.
Four players take the court across the net from each other at the baseline. One team feeds. Both players on this team feed one ball each so that two balls are in play at the same time. Each player plays straight ahead only with their opponent. When someone misses, they yell 'Crash' and all four players must rush to the net and play out the remaining ball/point. If someone fails to rush the net, their team loses the point. First team to 11 points wins.