Perfect time of the year too. Very easy to build.
I agree with the adirondack chair suggestion as well.
There are very simple designs out there plus its a great opportunity to try out different techniques, depending on your design. You can get plenty of practice on simple routing and joinery, as well as using your spiffy new power tools without risking a lot of time and effort.
Don't forget to take care with finishing. I've seen plenty of people do a bang up job in the construction, but rush the finish and ruin a job.
welcome to the addictive world of woodworking.