Sometimes you need to rbind multiple data frames. do.call() will let you do that (someone had to explain this to me when bind I asked this question, as it doesn't appear to be an obvious use).
foo <- list()
foo[[1]] <- data.frame(a=1:5, b=11:15)
foo[[2]] <- data.frame(a=101:105, b=111:115)
foo[[3]] <- data.frame(a=200:210, b=300:310)
do.call(rbind, foo)
