Fushimi Inari Shrine is one of those places that I really didn’t know about, but I was actually really glad when I went. It’s a bit difficult to access from the rest of Kyoto, but it’s definitely worth it. Basically, Fushimi Inari is famous for the hundreds of Torii (gates). It’s not just the gates, and it’s part of a temple complex that is quite nice overall. Basically the gates are parts of trails, and you get to walk through them. They make for nice pictures, but it can be a bit difficult at times to actually take the pictures because of people at times.
The Torii come in sizes big and small. If you donate a fixed amount of money, you get a Torii with your name (or your company’s name) on it, along with your address. According to the sign I saw (4th picture), these start at 175,000 yen (and for a small one the size of a textbook, I assume).
Note that the trail here goes up a mountain and can take a few hours, but of course you can stop midway and go back. Still, this is definitely a must-visit place. The mountain has some nice views on the way up as well. Also note that this is something you need walking shoes for, as it involves quite a bit of walking. There are some shops in the temple selling expensive water and some good luck charms and a lot of touristy places by the station, but the best bet is to take some drinks with you.
As it is outside, there is no opening/closing times (although keep this in mind during inclement weather). Also, keep in mind that this is basically a shaded mountain, so it can be a bit cooler than near the station.
Fushimi Inari is easily reached from either Keihan Fushimi Inari station (which has an interesting design based on Fushimi Inari) or JR Inari station.