5. Lemmings
Psygnosis' immensely popular platform strategy series Lemmings is addictive for two big reasons; it boasts an ingenious concept and has a fair degree of challenge to it. Each level begins with a box opening up, which releases a large number of anthropomorphic rodents who amble aimlessly in which ever direction they're facing out of the box. They'll keep walking forward - even if this means to their death - unless you help them, so you must use quick-thinking to save them from their own stupidity, by building bridges, walls and so on so that as many Lemmings as possible can reach the exit of the level. The game's sheer difficulty is perfectly pitched such that you'll often miss saving the Lemmings by just a nose, so you'll be angry but also eager to keep playing. Cut to three hours later, and you've finally done it, before noticing your wife has left a note on the kitchen table saying she's going to her parents' for the weekend.