Punch is the answer. It's relatively easy to do, and as your guests drink and the ice melts, they're getting more water and less booze which will keep your house from looking like Jonestown in the morning.
To add on to this, here's Dave Wondrich's Rum Punch recipe. If you want to up the booze some, substitute a dry sparkling wine and a cup of water for the quart of water.
4 large lemons, peeled with little to no pith
3/4 cup sugar
3/4 cup strained lemon juice from the 4 lemons above
1 750ml bottle rum (use something funky like a Jamaican rum, white rum won't work for this)
1 quart of water (or 1 750ml bottle dry sparkling wine and 1 cup of water)
Lots of ice
Nutmeg
Add the lemon peels and sugar to a quart mason jar. Let it sit for 4-8 hours. Then add the lemon juice, and shake to dissolve the sugar. Dump the entire contents into your punch bowl, and add the rum, water (or sparkling wine and water), and the ice. Grate nutmeg over the top, and serve.