I was recently able to try Castle Ravenloft. My first thoughts looking at the box was oh look Wizards made their own Hero Quest Game. I don't play D&D but the guys I tested this with do, and they informed me it's a really simplified version of the 4th edition rules.
The components are very nice, in the box you get a ton of plastic miniatures, heavy card stock: dungeon tiles, character cards, tokens, and markers. The box also includes a rules manual, and adventure guide. There are also several decks of cards. My only issue with the components is the fact that the "organizer" forces you to pile everything together and there's not separators for the card decks. I've seen several good solutions on boardgamegeek.com, but it would be nice if the box came with a better way to organize all the parts. As it stands you either spend a significant amount of time sorting prior to play or interrupt the game to dig for the needed piece, marker or token.
Game play is really easy and intuitive. Each player has a card that lists the order of play. The phases consist of Hero Phase: fight, move etc; Exploration Phase: place new tile, encounter etc; Villian Phase: monters, traps etc drawn by the active player move, fight etc.
Aside from what is dictated by the adventure guide, everything that happens in the game is determined by on of several decks of cards. This means that no adventure will ever be exactly the same. The dungeon is also drawn randomly from a stack of tiles so it will also rarely be exactly the same.
Combat is simply a matter of rolling a D20, adding the total to your modifier and comparing it to the AC of whatever your attacking. You then apply the damage and if the damage exceeds the wounds you destroy the monster and draw a treasure.
This is a really fun game and I can see it popping out as a filler between larger games or playing several adventures over the course of an evening. The components are very nice and of a good quality and I imagine that expansions will be made in the future. Although because of the random generation of events it will probably take a while to grow bored with what you get in the box.