I did the games for my friend's shower - I've listed the ones that match your criteria best, but if you're interested, I have others. I had a lot of pen and paper games, but most of them were very tasteful.
The traditional one is the "don't say baby" game - no one is allowed to say the word "baby" the whole time. In one version, each guest gets a clothespin (diaper pin, whatever - something they can attach to their clothes) and if they say baby they lose the pin to the person who catches them. At the end of the shower, the person with the most pins wins.
My favorite was "the perfect baby" - Before the party, the mother-to-be fills in a list of attributes (eyes, teeth, sense of humor, etc.) with whether she'd rather the baby get hers or her husbands (e.g. my teeth, hubby's eyes, etc.) At the party, the guests try to guess which one she picked. In the paper version, each guest fills out a scorecard and the person with the most matches wins. But it could easily just be a group vote type of activity or a show of hands, without the prizes.
Another good one is "a mother's purse." Everyone gets out their purse and you read off a list of items. Different items are worth different amounts of points (e.g., a pen is worth one point, but a pacifier is worth three). The person with the most points wins.
I have sheets for these games, plus other pen and pencil games if you get desperate.
Good luck - it sounds like you're working under some tricky restrictions!