Walkways are a common use for pea gravel. The larger gravel works best since it stays in place better and won't scatter easily from foot traffic. It is wise to line the walkway with a border material to help retain the gravel. You can use pressure-treated lumber, metal landscape border, or even the plastic garden edging material. It is a good idea to put some plastic on the ground below the pea gravel to prevent weeds.
Pea gravel makes an excellent bedding for patio and walkway pavers. Whether you are using concrete or stone pavers you can easily bury them in a bed of pea gravel. Just make sure the gravel bed is at least a little bit thicker than the pavers. You can move the pavers side-to-side and sink them into the pea gravel quite easily. Again, use some plastic beneath the gravel to prevent weeds.
Use the smooth type of pea gravel to cover the ground around swing sets and play areas. In these instances it is best to slope the ground slightly so water will run to the edges of the play area, and then put down a thick layer of rounded-stone pea gravel--6 inches at least.
Use the larger sizes of pea gravel to cover driveways. You should crown the center of the drive slightly so moisture will run to the sides. Then compact the soil and add the pea gravel to a depth of 4 to 6 inches.
Use pea gravel to improve drainage wherever water builds up from rain runoff. Dig a hole and fill it with pea gravel. Excess water from the surrounding soil will flow into the pea gravel to fill the voids between stones. The surrounding soil will stay drier. This technique is often used for collecting water from building downspouts where there is no easy or aesthetically pleasing way to channel it away from the building.
A variation to this is to add a sump pump that will start up automatically when the water reaches a certain level and pump the water out of the hole, and away from the wet area, either through an underground or above-ground pipe.