how to downgrade packages using the current repositories?

[HeadHunter00]

Well, recently I added the xorg edgers repository. Bad idea, everything starts freezing after I run more than two applications and nothing responds. I used to mess around with the updates all the time in arch linux, and then remove the bleeding edge repository and then downgrade every package that way. I just wanted to know if thats possible in ubuntu?

[HeadHunter00]

I looked everywhere and figured that you can't do that with apt. So, I just reinstalled the system and started using deja dup before doing anything stupid.