Absinthe is an herb-based liquor. It is usually either clear (blanche or lebleue) or green (verte). If you have a taste for anise, hyssop, fennel and similar herbs, you will probably like it. Some compare it to licorice in the way it smells, but you can hate black licorice and still like absinthe. Preparation is often the biggest factor in whether you will or won't like it. Drinking it straight, in shots is a very, very bad idea. The alcohol can be almost 70% (compared to whiskey at 40-45% and Jaegermeister at 35%). It will destroy you (and this is part of where it got its "dangerous" reputation).
Proper preparation is 1 part (usually 1-1/2oz) Absinthe in a glass, then slowly drip ice cold water into the glass until it louches (becomes cloudy) and the mix is about 4 parts water to 1 part Absinthe. Some choose to place an absinthe spoon with a sugar cube on top of the glass and drip the water over the sugar. This will make a very sweet drink.
Notice I did not mention lighting it on fire. This is a contribution of Hollywood and not part of tradition. Also putting fire near 70% alcohol can result in you looking like Freddy Krueger.
Last part. Drink sloooooooooooooow. Like your pipe, sip, don't gulp. Drinking too much absinthe too fast will give you the most brutal hangover in the world. Worse than Tequila, even.