There is a new coin called Yenten that is CPU only and growing popular. You can get a good hashrate with even fairly old computers including laptops. I'm mining it on two laptops and a pretty powerful desktop all running Linux, so you should have no issues. Check here:

https://bitcointalk.org/index.php?topic=2329470.msg23686620#msg23686620

for more info and a link to the Github page to download the wallet/miner. You will need to compile both from source but there are instructions given.