I just did such a course.. (Score 1)

I'm an undergraduate student and just finished a course in VHDL implemented on the Xilinx Spartan3-series FPGA and found it highly enjoyable. Definitely don't attempt to cram both in one module as I have no doubt that would confuse the kids no end. Instead get them comfortable with one and take that a bit further. I found Verilog a bit less intuitive but I did spend less time studying it.