We rented boards for $10usd each for half a day from Frijoles Locos. They weren't long boards, so it took us ages to get used to them. We had the waves all to ourselves for hours. The beach here is gorgeous too - white sands and mangroves as the backdrop.
In the afternoon we looked around the surf shops in Tamarindo. It was a world away from Playa Grande and completely packed with foreigners. It wasn't for us (very resort like) but if you like the home comforts and beautiful looking people then head there.
We headed further south to Playa Avellanas. It was busy as it was the weekend (and the Christmas period), but we heard good things about Lola's bar (rated one of the best in the world apparently). Although the menu is short, the food was fresh and simply awesome. It's not a cheap place, but you pay for the location (it's right on the beach). The only downside was that it was a bit disorganised and we had to wait an hour for a table. Still, definitely worth the splurge.
For sunset we went to quieter Playa Negro (10 minutes away). It was one of those 'I'm so lucky to be here' moments and as we had our cold beers and BBQ we knew that this country would be a hard to leave.