I will be living in Valladolid from the end of August to the middle of December. I will be there for study abroad and I was wanting to know some good trips around the country I can take during the weekends, and/or any specific festivals I should go to. I am living on a student budget. ANY help would be very much appreciated! Thanks!

You can visit lots of interesting towns : Salamanca, Zamora, Palencia, Segovia, Cuéllar, Peñafiel......
About festivals I don't know, but sure that you can find some in september with the pick up of the grape...