I recently downloaded 'Blood Bowl' on Steam to my Mac, not realizing that it was not Mac-compatible. Is there any software or any way that will allow me to play it, as obviously I've already paid for it? Cheers.
If you have access to a copy of Windows lying around, there's always the option of running the game in a virtual machine. Note that by running Windows in a virtual machine, you will naturally take a bit of a hit in performance. Give the virtual machine access to a large chunk of your system's resources and you should be fine though.
While I've never run games in a virtual machine myself (I use virtual machines principally for Linux installs), I checked out the community's forums and it looks like it is a fairly common task. It can be a daunting task for an inexperienced user, but the actual virtual machine application makes it a very simple process.
Another option would be to simply utilize Mac's Boot Camp to put a copy of Windows on another partition on your hard drive and run it from there. Both of these tasks though require a copy of Windows on hand, so if you're lacking in that area, my apologies.
The best option is to purchase (or find an old copy) of Windows and install it either in Boot Camp or Parallels (or some other virtualization software). Boot Camp will provide the best performance, but means rebooting in order to play your game. A VM won't provide the same level of performance (although it's close), but is usually more convenient. Using WINE is an option, but as far as I know, it can't out-perform a VM.
There's something to be said about having native Windows graphics drivers, which you won't get with WINE.
Any method that will let you play Windows games on a Mac is going to be WINE-based, the only difference is how well the game plays (possibly tweaked through configuration) and how easy it is to set up for the end user.
You can check out running games through WINE yourself at the official WINE site.
Alternatively, a community known as Porting Team does quite a bit of WINE packaging that's easy to set up for an end user. In particular, they have the Windows version of Steam that you can run through WINE and you can at least attempt to run Windows games downloaded from that version of Steam. Not everything works all the time but I've successfully played both Civ V and Alien Swarm through Windows Steam on the Mac. I'd check the Porting Team site to see if they have support for Blood Bowl.
CrossOver seems to work well for most games.
Their website for their Gaming product is http://www.codeweavers.com/products/cxgames/