Yesterday one of our accomplished gamemasters brought his "Dungeon Crawl that fits in a shoebox" with him. He used D&D Fourth Edition with some homegrown tweaks. For miniatures he tried to get a hold on as many old Citadel miniatures as he could.
You can see more pictures of the Dungeon here (if you need something translated, just comment below):
You moving forward, more tiles would be added and more grim foes would jump out of the shadows. The only flaw that the game had was that it was not in 15mm ;) Smaller figures leads to bigger Dungeon space for the same money/work, leads to more possibilities, bigger monsters in comparision etc....
The mighty heroes gather. From left to right in MMORPG terms, the Dwarf tank, the half-elf rogue/assasine, the damage-dealer mage and the support/healer druid (played by me).