Each agent chooses when to invest (if at all) and observes the number of investments by others in each period. That number provides a signal on the private information of other agents about the state of nature. The waiting game has in general multiple equilibria. An equilibrium depends on the intertemporal arbitrage between the opportunity cost of delay and the value of the information that is gained from more observations. The informational externality generates strategic substitutabilities and complementarities. Multiple equilibria appear, which exhibit a rush of activity or delays and generate a small or large amount of information. The convergence of beliefs and the occurrence of herds are analyzed under a variety of assumptions about the boundedness of the distribution of private beliefs, the number of agents, the existence of an observation noise, the length of the periods, and the discreteness of investment decisions.