I started this show not knowing who The Flash was; even -what- the Flash was. I was not a big comic reader. But he quickly became one of my favorite characters and this is one of the episodes that shows why.
Wally is often used as comic relief in this show, but there is a deeper side that often shines through during the show's run. While this episode clearly goes for the humorous route, we still get to see just how -powerful- The Flash is, and how dangerous.
One memorable scene is where it is explained to us why Wally never uses the full potential of his power: the result could be devestating. Wally is so often shown as the carefree youngster of the group that sometimes we forget -why- he is one of the founders.
There are numerous laugh out loud moments as Wally tries to pass off as Luthor, and Lex-Flash tries to escape the Tower. The bathroom scenes of both characters are classics and will most likely be ranked as some of the funniest moments of this show's run.
Still, even given the full run of Luthor's hideout, Flash remains true to his character and learns absolutely nothing of value during his tenure as Luthor. And we're reminded of Luthor's evil genius as he reveals just the amount of control he has over his team of villains.
There is also a questionable scene where it is heavily hinted that Wally and the witch were having 'fun' in his room. I doubt kids would get it, but adults are sure to laugh as they watch.
Overall, this is one episode I know I would be able to re-watch and still find amusing.