I recently picked up Arkham Horror board game second hand for a steal at 25 quid delivered. So I forced the Mrs to play this weekend.
I have to say despite being lengthy I really enjoyed it. It scales really well for whatever number of players too.. And I find finding games that run well for 2 don't often run well for more and vice verse but this really will.
It terms of gameplay its quite similar to pandemic in terms of the bad stuff happening but alot more to it.
Effectively you have to stop doom spreading to much in each neighbourhood all the while collecting clues to progress the story and kill the big bad or in this case stop the ritual!
Would definitely recommend.