There's probably no statistical evidence to prove it, but there must be a relational corollary among horses, gambling and alcohol. Two cannot exist without some love for the third — a holy trinity of good times. You can kill three birds with a huge rock this weekend when Colonial Downs holds its second annual Rhythm, Bets 'N Brews Festival. Featuring thoroughbred racing and the Colonial Turf Cup, the venue also will float on more than two dozen microbrews, with food and music Saturday, June 20, 11 a.m.-7 p.m. See what happens when a horse gets a little too much to drink and bets against himself. A sampling mug and tickets for five samples are $10 (additional tickets $1 each). 10515 Colonial Downs Parkway, New Kent. 966-7223. — Mike Hilleary