To get more people playing (and probably paying), Niantic has been holding "Community Days" in Pokemon Go for the last two months. On a specified day for a couple of hours, the spawn rate of a relatively hard to catch Pokemon gets increased so that players can have an opportunity to catch and evolve their favorite critters. For March's event, Bulbasaur will be in the spotlight.
Taking place on March 25, 2018 from 11:00 am - 2:00 pm CEST, players will be able to find an influx of the grass Pokemon around their hometowns. As with February's Dratini event, any critters evolved into Venasaur will get a special move for raid battles, though that move hasn't been announced yet. The event will also have a triple XP bonus along with special three hour lures to help you power level.
Seeing as how I only catch about five random Pokemon on my way to the gym, I've remained pretty static at level 24 for awhile, so this could be a great way for me to finally level up a bit. If nothing else, I can finally find a Bulbasaur.
Pokémon GO March Community Day: Bulbasaur, 3x Catch XP [Pokemon Go Hub]
via destructoid https://www.destructoid.com/pokemon-go-s-third-community-event-will-feature-bulbasaur-491908.phtml