Speakezee

Speakezee is a platform that connects expert scientists interested in speaking with the public with event organizers.

Source – https://www.speakezee.org/

Cafe Scientifique

Cafe Scientique is a set of meetings where scientists take turns presenting on their topics in casual local venues such as cafes, restaurants, bars, and theaters. You can volunteer to present at a Cafe Scientifique meeting in your city.

Source – http://www.cafescientifique.org/index.php?option=com_content&view=article&id=91&Itemid=435

Science Cafes

Science Cafés are events that take place in casual settings such as pubs and coffeehouses, are open to everyone, and feature an engaging conversation with a scientist about a particular topic. Venues range from a local library or coffee house to a neighborhood bar. Even the names of Science Cafés vary, including Science on Tap, Science Pub, Ask a Scientist, and Café Sci.

Source – http://www.sciencecafes.org/

Nerd Night

Nerd Nite is a monthly event held in more than 80 cities during which several researcher volunteers give 18-21 min "fun-yet-informative" presentations on their subjects, while the audience drinks along. You can volunteer to present to interested people from across disciplines in a casual, beer drinking, setting.

Source – http://nerdnite.com/