The Nevada State Museum is a wonderful museum and everybody should visit if you get an opportunity. They raised the rates to get in to $8 per person, but it was really worth the money.
They have an exhibit of slot machines that were made by Charles Fey. The original Libery Bell slot was spring loaded and had three reels bearing strips of symbols: bells, horseshoes, stars and card suits. The player would put a nickel into a slot and pull a handle on the side to compress the springs. When released, the springs would expand to send the reels spinning until stopped by a separate mechanism. If the symbols matched, the player won a "jack-pot".
Also on display is Historic Coin Press no 1. This is the press that minted the first coins at the branch mint in Carson City in 1870. This press minted millions and millions of silver and gold coins.
There is an Underground Mine Self Tour - where they have built an almost exact replica of a mine. You can also visit a ghost town that they have built in the museum.