[u]Basic (rough) plot:[/u]
The crisp morning air tells of the change from summer into autumn. Staring up as the house in front of you, you take a deep breath to calm your nerves. This is it. 34 Newton Road. Your home for the next year as you carry out your education at Cambrucks University. 
The house itself was a lucky find; 3 floors with a converted basement as well, 5 bedrooms, 2 showers, large garden and all of it stood a little less than 2 miles from the university itself. The rent had been ridiculously cheap as well for the area even split between your housemates. The little old lady who owned the house had asked for 4 months rent upfront, you hadn't thought much about it at first, just a little old lady needing a bit of money pronto. It was only upon living in the house you realised the truth. The house was infested with demons.


Ok, so the basic idea is that 2-5 uni students move into a house share which is already home to 2-4 demons, however since they have already paid 4 months of rent to their sweet old landlady they're stuck whether they like it or not in the house for a minimum of 4 months.
The demons who live in the house feed of emotions, so for them students living in the house is somewhat ideal. Each demon has a preference in the emotion they consume which comes down to the type of demon they are. This means that each demon messes with the students in specific ways to benefit them (make the students produce their preferred emotions).
The demons can chose to let themselves be seen by the students, however this is only for the students inhabiting the house and the landlady. Outsiders cannot see/hear the demons. If an outsider calls upon a demon through some sort of ritual then the outsider can see the demon from that point onwards but they will then receive the same amount of harassment as the inhabitants. 
The demons abilities only really stretch from manipulation to interaction with the physical plane. Other abilities can be allowed but I'm trying to avoid allowing god modelling. PM me if you want to discuss any.
Demons don't need to sleep or eat however they may have a preference to do so.

I think I've covered all of my ideas now.
Is anyone interested?