A practical example, of one who found his children to be lacking and gave all of his property to Yonatan ben Uziel instead of to his official heirs. The sage gave a portion of that gift back to the children, which opened a tussle with Shammai, over the standing of the benefactor's wishes. Also, the 80 students of Hillel the Elder, and their greatness, including the least of them being R. Yochanan ben Zakkai, and how accomplished and steadfast he was in learning Torah. Also, a new mishnah! When man who specifies his heirs, he's largely believed - and then his wife would be proven exempt from yibum. Which is more of a "yibum" issue than an "inheritance" issue, but it applies to both.