Here's how (click here for a recipe for broiled oysters on the half shell).
1. Set the oyster on a kitchen towel to prevent it from slipping as you shuck.
2. Gripping the oyster firmly, insert the tip of an oyster knife into the hinge. Twist until the hinge breaks.
3. Draw the blade of the knife along the inside of the top shell to ease the shell up and off.
4. Run the blade along the middle of the top shell to sever the adductor muscle, which connects the shell to the oyster's flesh. Discard top shell.
5. Draw the blade along the bottom shell to free the flesh completely, being careful not to spill any of the briny liquid.
6. Use the tip of the oyster knife to remove any shards of shell that might have fallen onto the flesh.