1. A system for planning and executing projects, the system comprising at least one memory storing computer-executable instructions and at least one processing unit for executing the instructions stored in the memory, the execution of the instructions resulting in the processor being programmed to provide one or more application modules comprising: a model specification module for creating a project model comprising tasks and dependencies among the tasks; a task complexity module for determining the complexity of the tasks and for modifying the tasks to maintain the complexity within predetermined bounds, the modifying comprising dividing a first one of the tasks into a plurality of separate tasks if the probability of completion, by a resource, of the first task is below a first threshold; a redundant task designation module for designating a second one of the tasks as a redundant task if the probability of completion of the second task is below a second threshold; and a task market module for (i) making the redundant tasks available in a task market for completion by a plurality of redundant resources participating in the task market, and (ii) limiting the number of redundant resources that may undertake a redundant task based on the probability of completion thereof.