I think there are materials that combined make a perfect marriage-that expression is almost an oxymoron, but they are very close those two-wood and concrete, especially reclaimed wood and concrete. This summer I plan to get involved with some projects implementing these materials, before I post my own work here, take a look at these amazing ideas, people are creative beyond measure I think.
Now, moulding the concrete blocks is really easy for the most part. There is a guy-Ben Uyeda that has some cool tips and tutorials, he uses Lego blocks and melamine boards to for the moulding then pours the concrete mix and gets the form to set for couple of days. These should be reinforced with some metal rods, or metal mash to make sure the structure is sound and fit for the purpose.
Making concrete furniture is a perfect way to fit your garden or a patio, they do not need much maintenance, and really-they are hard to destroy, even for a seasoned trouble maker.
Have fun creating your own stuff.