I used to love Pushover. Not only was it sponsored by Quavers (one of the mightiest of crisps), but it was a pretty funny little puzzle game. No idea if they did a follow up or not.

Games that me and my friends got the most excited over tended to be fairly run of the mill ones. Dungeon Keeper was something that me and my friend Mark got really into. I remember once it being time for me to go home but we convinced my Dad to let me stay ten minutes or so extra to see what would happen if we levelled up a Horned Reaper to level 10. Not sure if you'd count Dungeon Keeper obscure (it's not as well known as Bullfrogs other games such as Theme Park and Theme Hospital), but it was a great game in its day. Used to like Jazz the Jackrabbit as well.