I first saw this project at this website: http://www.notmartha.org/tomake/marblemagnets/
This project turned out nicely, with minimal effort/supplies, and would be a good project for kids (who can use scissors and glue).
For the project you will need glass bobbles/marbles, (I found mine at a fabric store, but they are also at local dollar stores too) mod podge, magnets and images of some kind that you want to use. I used an old map, but there are oodles of options-pictures, (copies) magazine images, words, scrapbook paper…..the glass marbles must have one flat side which is the side you will adhere your image to and the magnet for hanging.
Start by cutting the images to the size of your glass marbles/bobbles. Each one varies a little, so you want to be pretty accurate. Apply one coat of Mod Podge to the flat side of the glass bobble and apply your image (so that it shows through the rounded side) and apply a second coat of Mod Podge to the backside of the image. You will make a Mod Podge sandwich, if you will, with your image in the middle.
After the Mod Podge dries, glue a magnet to the back and let that dry. Then your project is complete! I used an old map of my local area, and cut out locations that were significant to me-my hometown, my work location, etc. My friends did this project with me, and one printed off map locations of all the cities she had traveled, my other friend cut out pretty images/destinations (the Eiffel Tower, etc.) from magazines and an old calendar. The only warning is that thick and glossy items (like actual photos) will not work well.
Note: You can see that I opted to use part of my map (from 1967) that explained the Illinois toll charge-approximated 2 1/4 cents for each mile! I got such a kick out of is because it’s quite a bit different now, and thought it made a great magnet 😉