Aeon seems to be related to Monero, and is a cryptonote currency.
What exactly is Aeon?
Quoting smooth, who is a member of the Monero core team and stepped in as Aeon lead developer a while ago:
AEON is certainly targeting running a node on a smartphone, but I don't think it is possible to completely rule out Monero (someday) doing that too.
As answered above by others the idea is to do experimental and perhaps even stupid things. Some of them may be adopted by Monero in time, others may not.
Also, as I said earlier in Monero's history when the clones were first appearing, what makes a coin stronger is defeating clones. (I reject the idea of expecting to stop cloning by trash talking clones or cloning, as Adam for example tries to do.) Every coin so defeated serves as credible evidence that the community, process, and technology of the original is sufficiently fit.
So you can think of AEON as a sparring partner to keep Monero healthy and strong. :)
Aeon is a fork of Monero, created in June 2014 by an anonymous developer. It was abandoned soon after, and languished for a while with close to no hash rate.
In October 2014, Monero developer smooth took over the fork and merged a handful of fixes and improvements from Monero, as well as changed the PoW and block time to be more friendly to smaller devices.
As this time, Aeon is expected to merge a lot of improvements from Monero in the not so distant future. It will retain a few differences from Monero: