Chastity game

Give the guests a clothespin (for each one) - you can also give beaded necklaces, plastic rings, or paper clips to sport upon arrival.  Welcome all by announcing that they have turned into virgins once passing your doorstep.

To continue being a virgin, one should not pronounce marriage while playing this.  If you find someone pronouncing the word, you can take their clothespin.  Aim at getting as many as you can.

Those who lost their pins can make others to say the banned word to recover their pin.  An alert person swipes another that has several clips takes them all.  For instance, if a number of people discover at the same time about the "error", the first to announce the lawbreaker receives her pins. In conclusion, the person having the maximum number of pins is the winner.
 
To tweak this, try making use of a number of gifts instead of pins.  The one who seizes others uttering the banned word gets all their possessions.

For variety, hand everyone three pins instead of one (so you can leave room for a few errors); to make it even more interesting, announce three words which are almost impractical to avoid, like sweet, the name of the bride, and so on.