ekscitiĝi

Two things are going on in this word and only one of them is Esperanto.

The Esperanto half is the ending. Eksciti is transitive: the news excites the town, and the town is the object. Add -iĝ- and you move the spotlight onto the thing it happens to - la urbo ekscitiĝis, the town got excited, with no one doing the exciting. That is the whole -ig- / -iĝ- contrast in one letter, and this verb is a clean place to practise it, because English uses the same word for both halves and gives you no help.

The other half is a warning the eksciti page already gives and which is worth repeating with the longer word in front of you, because the longer word makes the trap look even better. Ekscit- is one indivisible borrowed root, from Latin excitare. It is not the Esperanto prefix ek- (sudden onset) plus a verb sciti, because sciti does not exist. What does exist, and what makes this genuinely confusing, is ekscii - ek- plus scii, to come to know, to find out. So the language really does contain an ek- word that starts with those five letters, and it means something entirely different. Mi eksciis is I found out. Mi ekscitiĝis is I got worked up. One letter apart, and no relation whatsoever.

On register: ekscitiĝi covers the whole range from a child on a birthday morning to a crowd getting dangerously stirred up. If you want only the happy end of it, ĝoji is safer.