Just any old PDF reader.
VLSI lab tasks are arguably the hardest in all of ECE. Not only is Cadence Virtuoso a confusing software, it is also very difficult to install on your personal desktop. (Most of the cracked versions don't work properly and a license for Cadence WILL burn a hole in your wallet)
So, the only remaining option which exists, is to painstakingly take out your free time and sit around and perform the tasks in the lab itself. (If the PhD. guys aren't hogging the systems that is..)
So, here are 4 PDFs, which contain most of the lab tasks you will need. (Download them all)
P.S. : Pay attention in the lab classes, this sort of treachery wont work for the lab exams. This is just to save you time in your 3rd year so you can prepare for your placments and competitive exams.
Pull requests and any corrections to the codes are welcome. I would certainly love to include any and all new lab tasks that I may have missed.