What should I do with 2 weeks in Costa Rica?

Hello Amit. I would suggest Guanacaste . It is a province of Costa Rica located at the northwest of the country and is home of beautiful beaches, mountain ranges and a number of volcanoes. I will name those beaches that I have visited and/or are my favorite ones. Tamarindo, Playa Conchal, Playa Flamingo, Del Coco Beach and Playa Hermosa. There are many national parks and volcanos nearby to visit. One of my favorite is Reserva Biológica Bosque Nuboso Monteverde and Arenal Volcano. If you have time and are more into relaxation, eco beach, surfing, etc., visit Playa Santa Teresa. It is located at the Nicoya pretty close to Guanacaste. I would suggest to rent a 4x4.

If you want another option I would say Limon.  Because it is located at the Caribbean side of the country, the beaches are absolutely gorgeous. Puerto Viejo de Talamanca, Cahuita , Gandoca Manzanilloand Tortuguero are my recommendations.

Osa Peninsula is another excellent option however in my opinion it is a bit far away from the city. 

I always suggest hotels, and things to do in each place. Not sure if you need this type of information as well. Please let me know if so.

Pura vida!!

PS / Here a few pics from my family album / December, 2014

This blog post might help. I was only there 9 days, so you'll have extra time to hang around a few places a bit longer.