Simply put, The Hunger Games is about a girl named Katniss who ends up playing the game of her life, a match to the death between 24 12-to-18 year olds who are chosen each year at a dreaded event called the reaping. Aside from the other contestants, each person must face "natural" obstacles engineered by the Gamemakers: forest fire, yellow jacket-like tracker jackers, ends-of-the-spectrum temperatures, and days-long thunderstorms.
As for whether or not I liked the book, well. This. Book. Is. Brilliant. And don't forget captivating, smart, at times sweet, and utterly unforgettable. I can't compare The Hunger Games to any other book I've read, but if you're an Uglies fan, this recommendation goes doubly for you. So, go. Read The Hunger Games now. What's that I hear? You've already read it? Well, read it again. It'll help you make it 'till the sequel. Oh yeah. There's a sequel. And even better? It comes out September 1st.