Here's a slightly more complicated example involving a join.
It shows how you can select all columns of the attendees table using the Symbol multiplication method without an argument, very similar to how you do so in SQL.
It shows how easy it is to join tables, by specifying a table name and conditions. See how Sequel assumes that the id column is for the events table and the event_id column is for the attendees table.
Finally, note how the bitwise operators on Symbol operate as the logical operators in SQL. The ampersand is used as AND, the pipe as OR, and the tilde as NOT.