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#msg23686620for 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.
don't need to compile any of them, they have the binaries already
other cpu only coins you can try are Magi and Verium