A sequence of random variables that converges in L1 but not almost surely is a sequence of Bernoulli random variables where the probability of success goes to 0 at a slow enough rate. Specifically, let Xn be a Bernoulli random variable with P(Xn = 1) = 1/n, then Xn converges to 0 in L1 but with positive probability Xn does not converge to 0.