What is the difference between National Guard and reserve? Besides one being state and the other being federal. Also what is active guard?

Aside from state and federal, differences are USAR units are all combat support and combat service support. There are no combat arms maneuver units in the USAR. Reserve CS and CSS units are meant to augment Regular Army units, corps down to bde level as whole units, or piecemeal. TRADOC has USAR drill sgt and instructor units that can mobilize and take over IET at a training base. ARNG is structured more like Regular Army maneuver commands, deployable as bde, divison level assets. USAR units get all their funding from the federal DOD budget. The ARNG gets a percentage of federal funding, but most comes out of the state budget. AGR- Active Guard/Reservist, is the term for a full time active duty guardsman or reservist. Most of those positions are administrative, recruiting, supply, and maintenance (3rd shop).

You hit the nail on the head - the National Guard is under state control (Title 32 normally, unless mobilized for federal duty, Title 10) and the Reserve is under federal control. Active Guard (AGR) are those individuals that are National Guard members essentially on active duty ("full time" Guard). After 20 qualifying years, AGR qualify for a "regular retirement" (traditional active duty retirement) while M-day National Guard (and regular Reserve members) gualify for a "non-regular retirement" (retirement pay is determined solely by points accrued and time of service does not matter).

As I read other folks responses above or below, wherever this response falls many if not all are correct in more depth answer.

A simple answer: Reserve does one weekend a month and generally 2 weeks during some point in the year, but can do more if you have an NCOES school or other type school. That's generally it unless you get deployed.

National Guard: same in aspect of one drill a month and 2 weeks AT usually during summer and more if you need schooling. Now the big difference is there are usually always some type of "job(s)" available, either AGR (Active Guard Reserve), or ADSW (Active Duty Special Work) or Federal Tech jobs which AGR and Tech you can build and retire from. AGR is more like Active Army or what many guardsmen call "Big Army" where your able to retire with the same benefits as someone in "Big Army" Federal Tech is your age plus years etc etc have to ad up to some number that's about all I know about that one.
Nice thing about Guard you get to pretty much choose your path career vs someone telling you what your going to do. Many many opportunities vs Reserves, and by no means am I dogging Reserves, Big Army or any other services as we all have our jobs and I respect all members of the services.

Hope this is kind of a simpler way of looking at the differences between Reserve and Guard. But like I said at the beginning much of what folks said is correct but in depth.

Good luck