No fruit says summer like peaches. While strawberries are at least nominally available most of the year, and plums and whatnot are shipped in from Chile or Israel or Baja California, and even cherries are somehow made available near Christmas, peaches are resolutely a late summer fruit.
The problem is, how do you pick them? Peaches may or may not be fragrant; the best way to check their ripeness is to press gently on the “cheek” of the peach. If it gives slightly, the peach is ready. (Some vendors really don't want you to do this; you can always just ask them to pick ripe peaches for you.)..
Peaches come in “white” and “yellow” varieties, with yellow being much more common, and in clingstone (which have to be cut off the stone) and freestone varieties. At this point in the season, most of the peaches available are freestone, which are frankly easier to deal with. Make sure you cut off the rough cellulose that connects the peach to the stone; it's not going to hurt you if you eat it, but it isn't very pleasant.
You'll see lots of varieties at the farmers' market; by far the most common is a yellow freestone peach called Elberta. This is the variety most commonly sold at grocery stores, but buying them at the farmers' market means they were tree-ripe when picked; peaches don't travel well. My favorite yellow variety is O'Henry, a red-streaked peach that has just enough acidity to make absolutely amazing pie, and my favorite white variety is Redwing, which holds together perfectly on the grill while maintaining its juiciness.
You may see flat, squat peaches; these are donut peaches, which are sweeter and smoother than normal peaches.
What do you eat with peaches? Well, besides standing over the sink, they make an excellent salad with arugula and burrata (fresh mozzarella that has been filled with cream). Kick up the usual cobbler or pie by grilling the peaches first until they just get grill marks; make ice cream, or buzz them up in a blender to make Bellinis à la Harry's Bar in Venice.