If the entire 2 weeks is devoted to FPGAs, you could go a very long way. I hadn't read the post with that in mind, I was thinking about an EE convention type thing where there are short presentations lasting well less than a day.
In 2 weeks you can get through all of the items that Sweeny and JPortici listed and then some. In fact, given a suitable development board, I don't see why you couldn't implement an entire CPU. No, it won't be a pipelined RISC machine or ARM processor but there are many small CPUs that could be implemented.
There are amazingly few structures that are implemented in VHDL. The trick is using each structure in the proper place with the correct signals. We have gates, obviously, and flops plus blocks such as registers, counters, decoders, encoders, priority trees and I have probably forgotten a couple. These basic building blocks are interconnected to create the end project. But once you know how to code these blocks, you use them over and over.
Finite State Machines (FSMs) are a little more complex and there are some real gotch'as in guaranteeing that every output is defined under all conditions but once you see how that is done, you won't forget. I can't begin to tell you how many times I was caught in this trap. Slow learner...
It could be a great class! I want to go! Alas, I'm too old...