Black Russian


1 part vodka
1 part Kahlua

Over ice in a lowball glass. A drink that is both sickly and strong. Some drinking establishments sell Tia Maria and vodka, with or without cola, as a Black Russian. It isn't, and it tastes even more sickly. Don't do it, kids.

White Russian


1 part vodka
1 part Kahlua
1 part cream

or, alternatively

1 part vodka
1 part white creme de cacao
1 part cream
nutmeg

The Kahlua version seems to be more popular, and is stirred and served over ice in a lowball glass. A less acute version substitutes two parts of milk for the cream.
The more traditional creme de cacao variant is shaken with ice, and then strained into a martini glass and decorated with nutmeg shavings. Go easy on the shaking, as it might cause curdling.