Here’s my favorite: load up a bunch of cloth diapers with butterscotch pudding. First one to finish eating it wins.
We’ve done the baby food tasting (duct tape over the label, guess what it is)
Giving everyone a bottle of water and having a race to finish (get everyone the same large flow nipple)
Put some small baby things in paper bags and have the guess by feel what they are. Mom to be gets the things. Baby socks. A small toy litle a rattle, those plastic keys, baby dishes, baby tylenol.
Right, which is why I said that it should only be played if you have the kind of group who would enjoy it (which would include the mother, of course). I do agree that you should get the go-ahead from the mom and also that it isn’t always appropriate (I didn’t play it at my cousin’s shower, as my grandmother and her friends were present). At every shower at which we did play it, however, it was the highlight of the party. YMMV.
Oh, and when you ask for permission from the mom-to-be, you should do it as far in advance as possible so that she has plenty of time to forget. 
Also, Anne Neville’s post reminded me of something that happened when I was planning the most recent shower I hosted. I’d made a list of games for the new mom to approve, and she most emphatically did not want to play “Guess the Girth”. In her words, “I already feel like a cow, and I don’t want to be reminded of how big I’m getting.” So I guess it’s always a good idea to get approval for all the games, since you never know what could make the mom uncomfortable.
If it were my baby shower, I’d want a Trivial Pursuit tournament. Or maybe poker. I’m firmly in TeaElle and aruvquan’s camp on this one.
A co-worker of mine was highly insulted when guests tried to initiate the yarn game at her shower. She was already sensitive about her weight gain, and this did not help matters. It seems kind of crass to me, as well.
How about a rousing game of Dungeons and Dragons? Or Mario Kart: Double Dash!!
[sub]What do you mean those are inappropriate? Says who?[/sub]
The version of this game we played used chocolate bars melted in a disposable diaper in the microwave and you had to identify the different bars (Baby Ruth, Hershey Almond, Reeces Peanut Cup, etc). Even though we KNEW it was candy, it was still hard to investigate the mess to identify it!
I had a blast sidling up alongside one of the Q-Tips (75+ year old aunts with puffy white hair) who did not know about this game, diaper in hand, and eating chunks of candy from the diaper. The looks on their faces were priceless. I was only able to do it twice (once each to a different Q-Tip), but it was funny both times.