I'm a graphic designer at a signmaking company. It's a relatively small company (about 8 or 9 employees and every now and then a few parttimers or a student work placement), but we have a huge amount of pretty big customers. We basically provide other companies with pretty much anything they can use to advertise themselves. This includes pens, billboards, banners, neon lettering, window tinting, full car wrapping (nothing like wrapping an entire Lancer Evo IX in carbon, let me tell you), stickers, clothing, etcetera.
On the side I run a small business with 3 guys I know from school, basically providing webdesign, visual effects, film & photo editing, promotional and logo design and so on. It's still pretty much in the starting phase but we got some nice jobs to do already. It's mostly about having fun though, none of us plan to actually make a living out of it. But you know, a few hundred bucks extra every now and then is always nice.