[Itchynugat]

I've always felt it to be so much funnier when a clown is pied by someone else, rather than pieing themself. Halloween is an excellent opportunity to clown around in public, but it's a delicate thing to look like a good funny clown. Your makeup has to be near perfect so as not to be scary, but your outfit ought to look like a silly costume.
Once you have to look right to be laughed at by kids and strangers, the real trick is getting any of them to pie you. If you simply offer to let them pie you, it spoils the gag and marks you as a weirdo. I was thinking a good alternative would be to setup a stand and a sign, possibly out of cardboard. A pie made of shaving cream clearly visible sits on the stand, and behind it a sign that reads "In case of clowns, throw pie."
After you set it up, walk a full block away, then come walking back past it. If nobody pies you, and the pie is still there, keep walking a block away in the other direction before turning around. If you still aren't pied after passing it from each direction, then carry it off, dare completed.