Something similar may have been suggested before but how about when Vader shouts "What!" (at the end of the rench run) you then cut to Terry Gilliam shouting "What!" from The Holy Grail. From this bit...
https://www.youtube.com/watch?v=qry9IeJnbNU
There may be other funny useses of the word "What" that people could suggest. Maybe Mace Windu's Force-Ghost could chime in with the Pulp Fiction "What" refrence (A callback to ROTR).