My trip to India is happening last minute, I had less then one week to apply and receive visa. e-Tourist Visa was my option: https://indianvisaonline.gov.in/visa/tvoa.html
e-Tourist Visa Facility is available for holders of passport: USA, Canada, Russia and many more. I applied on Monday, on Tuesday I already had my approval, sent by email.
I completed a looong form online (at the bottom of the link you will see a clear step by step application process). Don’t forget to get a copy of your passport, saved in a pdf format (should have at least 6 month left), and a portrait of yours (it is important to follow all the dimensions and file size described on the site).
Fee was something like $40.
I received my visa number by email also saying that i have a single entry and should enter the country within these dates. A single entry is fine for me in this trip, but if you are planning to come back to India again, you probably should complete an application clearly stating that you will be re-enterina the country.
Also, not sure what should I be showing when entering the country,, I guess will just need to print out that email.