If you're feeling nostalgic about the DOS era and the associated hackery, give PCem a try:
It's an x86 emulator that works on hardware level (so from BIOS on, you're running real code that was running on those DOS machines), and with a focus on emulating the hardware from that era specifically, ranging from the earliest 8086 machines and MDA adapters, and up to 3dfx Voodoo era. Obviously this is mostly useful for gaming, but if you wanted to hack around with TASM or Borland Pascal just like in good old times, it's also great.