Make a sacrafice to the Plumbing Gods soon.
I recommend a virgin bottle of Liquid Plummer. Lay it on the altar, step back, and let the Plumbing Gods have their way.
I do not recommend sacraficing an entire entree of old spagetti. The Plumbing Gods do not like old spagetti. You won't eat it, why should They?
They especially do not like it when you put it in the garbage disposal. Their wrath is mighty and inconvenient. They'll show their disapproval by not allowing anything down their portal of magnificence aka the sink.
So you will be forced to wash dishes in the bathroom sink. Or worse, outside using the hose. This is not fun.
And being the insignificant mortal that you are, you'll try to make yourself feel better, feel cleaner by doing a load of laundy.
MUHA STUPID MORTAL! NOTHING SHALL PASS THESE PIPES!
Now you are stuck with a clogged sink and a load of laundry sitting in old bubbles while the washing machine bleeds out its lathery innards.
So silly. Such a silly little stupid mortal. Feel the wrath of The Plumbing Gods.
To make it up to them, first apologize to the housemate that you are subletting from. Tell them that you did not intend to cause such misery to be bestowed apon their household. Accept their recognition that you are only a silly little mortal and did not intend to cause harm to the Plumbing Gods. Now, offer to sit around until the nice landlord comes. Apologize to him as well. Find buckets, paper towels, offer to make him an egg salad sanwich. Then get the fuck out of his way, for the incantation is harsh and cruel and filled with the soul of spagetti gone bad.
All you can do is wait. Wait and hope that this will never ever happen again.