What can I do with my concrete slab ~10 ft by 15 ft ?

Garage sale an older outdoor table and chairs, spray paint bright cerise pink. Add a large potted palm from a market, a market umbrella, and get an old weatherproof set of shelves which can be arranged on a few concrete blocks for one side of the pation. (I bought 3 thick glass shelves for $5.from a closing business) Paint the blocks with sealer, then coat with same cerise paint as dining set. If there is a higher tree or wall nearby, hang a few solar lanterns etc. If able, put a cheap grass matt under the table etc. Roll it up and store when the weather is bad. Hey presto, a useable BBQ or sitting area for almost nix!

http://www.hgtv.com/videos/painting-concrete-patio-floor-0126635

This is cool too!

give it a good scrubbing, and use a concrete sealer. caulk the cracks. then a nice out door rug, or paint one on -but do that before you seal it. there are 10 ft square canopies, watch for sales around around memorial day. looks like electric is available - a few shepherds hooks to hold up strings of light. path lights at the edge of the concrete...my moms vision is poor...she couldn't see the edge of the concrete patio and did a face plant.

you can get rubber tiles in a few different sizes. the can cushion the hard cement. they do not lock together....i forget what the installer used.

Something that I think is really pretty is snap in deck tiles

https://www.amazon.com/tiles-each-EasyLink-Deck-Tile/dp/B0081IP03K

Definitely paint it to your taste, use an outdoor rug under or on the edge of your seating area to create a focal point. Paint some cool lanterns to place around for accent and subtle lighting. I would add a fire pit as well as some tall potted plants native to your area or plant some hearty shrubs around the edge to create the feel of a room while keeping them trimmed so you can sit and enjoy the view of your back area. Add more seating with colorful cushions, such as a bench.

Concrete stain comes in many colors

You can clean and fix the cracks. Remove the cement blocks and bricks on the ground around it. Then you can tile over it. There are many options to tiling. Trim down the grass behind the table and chairs. Put in some small evergreen shrubs and flowering plants around the patio. Paint the table and chairs a bright happy color and get cushions for the chairs. And get some more seating, like a love seat and end tables. And maybe think about an awning to give you some shade and a little protection from a light rain.

stain it instead of paint, then put a outdoor carpet and some furniture on it to dress it up, use posted plants, solar lights,windchimes in the yard.

Hire a Mariache band and have a party? :)

Stencil it! Many ideas at Hometalk.

I can't see the cracks in the slab on this monitor.

We took a similar slab and turned it into an outdoor room like the other posters. I started by faux finishing the concrete into tile using this tutorial. http://farmfreshvintagefinds.com/barn-makeover-stain-concrete-part-2/

We then added strawberry pots, director's chairs and a refinished $2 coffee table that I sealed with marine grade sealer.

I have the same slab situation leading upto my front steps. I am going to stain it in different colors in a slate pattern. Good luck to you