Saw this really simple tests for getting a sense of how healthy & fit you feel. I haven't done them myself yet but what I'm planning to do is write down how I think I will do on each of these and then see how I actually do. There's only four tests so do them with me and post how fit you are!

Wall push-ups in 1 minute: Stand facing a wall, about an arms length away with your feet placed a little wider than your shoulder width. Bend your knees slightly and put your hands on the wall with your arms out straight. Make sure you don't arch your back and keep your body in a straight line as you do push-ups against the wall. Bend your elbows at no more than a 90 degree angle and push back out. That's your first push up. Get someone to time you and see how many you can do in 1 minute. Here's how you rate:
Didn't make it to a full minute - beginner
0-25 - Okay, but room to improve
26-50 - Right where you want to be
55+ - Power to spare

Chair squats in 1 minute: With a chair behind you, stand with your feet slightly wider than shoulder width. Bend your knees as if you're going to sit but stop just before your butt makes contact with the chair. Return to standing position. Count how many you can do in one minute.
Didn't finish the whole minute - Need work
0-25 - not bad
26-50 - Sweet!
55+ - Top-notch athlete

1-mile walk/jog/run: Find a school track or level trail where a mile course is marked. Walk, jog or run the mile as quickly as you can safely do it. Rest if you need to but keep the stopwatch running. This test is a good indicator of overall cardiovascular fitness.
Didn't finish the one mile - Slow going
Did mile in 25 to 35 minutes - Fair to middling
Took 15 to 24 minutes - Where you want to be
12 minutes or less - You're fast!

Last one - Single-leg balance: With the floor clear & flat around you, stand with your feet about shoulder width apart. Lift one leg, with knee bent, in front of you for as long as you can, up to 3 minutes. Repeat with your other leg and record your times.
Couldn't hold up leg - wobbly
1 minute - Okay, but can be better
2 minutes - In the good zone
3+ minutes - You're floating now