It has already been stated that taxes can be used to appoint agents to carry out public works projects. Included in this, I believe, should be the option to appoint an agent to research a certain technology with research grants. On completion, a knowledge object should be given to all people who currently have a say in the government. Maybe funds earned from trying to sell this object should go straight to the government? Another interesting form of public works would be environmental restoration projects like replanting trees, setting up reservations for endangered species, combating water pollution, etc.
Actually, with the zoning system, game reservations could totally be a thing, right? For example, killing certain species inside of it would be illegal regardless of your current quota. And if pvp justice systems make it in, players could place a steeper penalty on poaching inside of a game reserve!
Also, I would like to propose giving players the option not to appoint an agent, and instead create a public contract like the ones that players can create. Then whoever feels fit to do the work can try. Players should be able to vote on the time limit, funds, and penalty for failure.