The Transit of Mercury is happening right now here on May 9th, 2016. If you want to watch live, check out the NASA feeds from the Solar Dynamics Observatory.
For the small size of Mercury, it makes a pretty stark contrast against the bright Sun, and is easy to see, even in a small telescope. Of course, you need a solar filter. Don’t look directly at the Sun without proper eye protection, you won’t see Mercury and you’ll damage your vision.
I managed to snag a photo on my phone through a small telescope. Please excuse the lack of quality since it was shot on potato.