Very simple… if you use items in pairs, so that your guests have to find their "match", and in order to do so, they have to talk to each other to find their "partner".

Some examples:

Jokes and Punch Lines
Person with the joke, "Why did the chicken cross the road"… has to match up with the person that has the answer, "To get to the other side". Great fun because answers with the wrong jokes are often quite humorous.

Puzzle Pieces
Before the party, put a puzzle together. Then select pairs of two puzzle pieces that fit/match each other from different parts of the puzzle. After all the pairs have been selected, take them apart and put all the pieces into a bowl for the guests to select one puzzle piece upon arrival. Leave the puzzle you’ve put together on a table so that as guess match up, they can put those pieces into the puzzle. Game is over when the puzzle is finished.

Colors
Before the party, cut two pieces of one color of felt or construction paper for every two guests. If there are twelve guests, you’ll need six colors.

Shapes
Cut each shape in half, planning on one shape for every two guests. Shapes include square, hexagon, circle, rectangle, pyramid, oval, thin strip, thick strip. The same shape can be used if the colors are different, for instance, red square, blue square, yellow square.

Song Lyrics

Select known songs, perhaps by age group. Teenage parties would require today songs, while an age fifties group would go with the "oldies but the goodies". Holiday parties can use appropriate songs. Select one song for every two guests. Each guest receives several lines of the beginning of a song and has to match the finishing lyrics another guest has.

Famous Movie Star Couples

These can be real life couples, such as Lauren Bacall and Humphrey Bogart or they can be movie couples, such as Samson and Delilah. Put one name of each couple on a piece of paper and pin to the back of one guest. Guests must ask questions to find out who they are, then go look for their "mate". Guests can NOT ask, "Who am I?".

Cartoon Character Couples

Same as the Movie Star couples above, but only cartoon characters, such as Charlie Brown and Snoopy, Garfield and Odie, Blondie and Dagwood, Dick Tracy and Tess.

Matching Fabric
Two pieces of each fabric pattern per two guests. Such patterns are plaids, stripes, polkadots, solid colors, felt, netting, and printed fabrics.
Party Favors
Use of small inexpensive party favors, two of each item for every two guests. Party favors include yoyo’s, party hats, whistles, bracelets, tops, blocks, crayons, rubber insects, etc.

Christmas Ornaments
Use of colored ornament balls, two of each color per two guests. Or use tinsel, bows, holly, ribbon, beads, bells, angels, etc. – things you hang on a holiday tree.

Holidays
Use small items to match your holiday party, whether it is Fourth of July, Easter or St. Patrick’s Day. For instance, if it is a Valentine’s Day party, use hearts, chocolate, Hershey Kisses, cards, cupids, etc.