The U.S. Mint is offering a wonderful program, where they offer sets of 250 $1 coins for $250, charged to a credit card, with free shipping. I just bought the maximum-currently-available of $2500 worth (2 sets of $250 for each of 5 presidents) with my cash-back credit card. I intend to deposit it all (maybe all except $25-$50 in coins to spend) in my bank as soon as it comes in. Between (1) the cash back on the item, (2) having the money in my checking account for roughly a month earning 4% interest, and (3) hitting the threshold for the much higher cash back tier a few months earlier, I expect to make north of $100 on the deal, for very little work.
Plus, it seems like a fun thing to try doing.