buying call and put at the same strike price with same expiration date called Straddle; at the different strike prices but with the same maturity called Strangle. #msg-24255776 Options Strategy: Straddles and Strangles
It is an art and need experience to play them well (luck too :) you can have potential to loss all your money or make a ton.
Recent example to play GOOG Strangle: #msg-28639335 set up on 3-28-2008: #msg-28024472 PUT went from 12.7 to zero, but CALL went from 6.7 to 80's at OE (4-18-08) due to ER effect