This is what the frame originally looked like- it had clearly been painted over several times:

There's been hot pink, black, and cream colored  paint on this frame at different times.

The inspiration for doing this came from a square frame seen at Michael's Craft Store. It was an incredibly easy DIY! If you have any loose photos, ticket stubs, postcards, or other little paraphernalia laying around and need a cute way to display it, this would be perfect!
Here's what you need:

• a frame (obviously). Like I said, I had one laying around, but it you need one, try checking a home decor store (such as Home Goods or Lowes) or a flea market! 
• spray paint
• jute twine, yarn, or other similar material for the lines
• hot glue gun
• scissors
• clothespins (I got miniature ones from Michael's, and they worked great! They sell them in a large variety of colors)

I cleaned off the frame by dusting it first- there were a lot of little crevices on this frame that needed cleaning. Then I just scrubbed it over with a damp washcloth and put it in the sun to dry.
The weather outside was unseasonably nice (65 in February??) so I took advantage of that and did all the spray painting in my yard. I set the frame up on two buckets and went over it in three layers. The black on the frame was a little tricky to cover up, but after that third layer it all disappeared. The spray paint I used was Krylon ColorMaster Paint+Primer in the color Ballet Slipper (satin finish).

Each layer of paint dried in about 8 minutes, but then I let it sit outside in the sun for awhile longer to try and let some of the paint smell fade away. After that, it was time to attach the lines.

And no, I didn't bother painting the back of the frame! :D

Luckily, the back of this frame had small holes in the back where it looked like mounting screws had been to hold a picture in place, and I didn't have to measure to mark where to attach the jute twine.
I cut out three lengths of the twine, leaving a little extra on each end just for wiggle room. Using a good-sized drop of hot glue, I set the twine down on one end, and then put another drop of glue on top of that.

For once, I didn't burn myself with the glue gun, either!

TIP: I would highly recommend waiting until one end of the twine is completely glued down before starting on the other end. You will want to pull firmly on the second end and hold it in place while the glue dries on it to ensure that the twine stays taut! If you don't, when you hang things on the twine it will droop dramatically. You don't want the twine to sag at all during this.

Finally, trim off any excess twine that wasn't glued down.

And- TA DA! That's basically it! All that's left now is hanging the frame up and decorating it!