Eclipse glasses are sold out pretty much everywhere in DC. I managed to get some of the last the Friends of the Library had in stock in Montgomery County yesterday. (They're sold out at both locations now.)
Thankfully, you can still get eclipse on Amazon, through a legit supplier (IE: one that you can buy glasses that will actually protect your eyes from damage).
If you have Amazon Prime, you can get eclipse glasses in time for Monday, BUT...be prepared to pay a pretty penny: your only option is to buy a 5-pack for $59.95. Here's the link to do it:
Monday, expect the partial eclipse to start at 1:18p. Max coverage happens at 2:42, and the waning partial eclipse will end at 4:01p.
If you can't get eclipse glasses (DON'T try to use regular sunglasses - they're about 1,000 times too light to protect your eyes against looking directly at the sun), NASA is going to live stream the eclipse starting at 11:45a. You can check that out here: