Maybe find out about getting a small business license? :-) An uncle did that years ago, partially so he could get into the Consumer Electronics Show in Chicago.
It looks like you can get a sole proprietor license for a home business in Wisconsin for $20 for 2 years, if I did my clicking correctly [link|http://www.wisconsin.gov/state/app/wizard/LoadIntro|here]. Dunno if it's worth the trouble though.
Cheers,
Scott.
(Who has never done anything like this himself, so caveat emptor, YMMV, IANAL, void where prohibitied, and all other standard disclaimers apply.)