After the fall of the Berlin Wall, Calta moved to the Netherlands and worked for The World Information Service on Energy (WISE[1]) in Amsterdam.
In 2004, he wrote a chapter of the book The Impossible Will Take a Little While (compiled by Paul Rogat Loeb), in which he detailed a successful campaign launched by an 18-year-old to overthrow the Bulgarian government.
[6] and co-managed the FAIRE project (Free & Applied Internships in Renewables and Efficiency) which trained Central European activists in English language skills, campaigning and then placed them in western environmental groups as interns.
In 1994, Calta presented materials before the US House of Representative Subcommittee on International Development to block the Export-Import Bank of the United States from funding the Temelín reactor.
[17] In late 2013, Calta co-founded the Point A project designed to start income sharing communities in urban centers on the East Coast of the US.
[22] The Flip Project brings out-of-state activists, organizers, street performers and artists to referendums and US Senate elections of national importance.
In 2018, Calta organized a group of intentional community members to canvass for the Florida state constitutional amendment restoring ex-felon voting rights.
In 2020, Calta organized another group of activists in an effort to unseat US Senator Susan Collins in Maine, by supporting Green Party Candidate Lisa Savage.
After losing in Maine, the Flip team went to Georgia, where they organized concerts, tiktok videos, free ride to the polls promotion, vote curing.
In 2022, Calta organized another group of activist to return for the re-election of Rev [Raphael Warnock] which was the only state wide election won by a Democrat that cycle.