We examine two commonly discussed institutions inducing turnout: abstention penalties (used in 32 countries) and lotteries rewarding one randomly chosen participant (as proposed on the 2006 Arizona ballot). We analyze a benchmark model in which voters vary in their information quality and participation is costly. We illustrate that both institutions can improve collective outcomes, though lotteries are a more effective instrument asymptotically. Experimentally, we provide strong evidence for selective participation: lab voters participate more when better informed or when institutionally induced. Lotteries fare better than fines, suggesting that they may be a useful alternative to commonly used compulsory voting schemes. (JEL C92, D72, D02)