USA Today has posted the the campaign committee price lists for Democrats and Republicans. For prices ranging from tens to hundreds of thousands of dollars, tickets can gain you access to members of Congress in various ways (parties, exclusive meetings, even strategically-located hotel rooms). Example: "House Democrats are offering a "premier package [$155,000]" at the Aug. 25-28 Denver convention that includes a ticket to a party honoring Speaker Nancy Pelosi [where the two of you may get to chat]
War On You: How Much Does the Ear of a Congressional Member Cost?