select * from v$sql;
You will notice that you can further filter on lot of useful stuff.
For eg: Lets say you want to see only those queries coming via a JDBC Thin Driver, you can do:
select LAST_LOAD_TIME, ELAPSED_TIME, MODULE, SQL_TEXT elasped from v$sql
WHERE MODULE='JDBC Thin Client'
ORDER BY LAST_LOAD_TIME DESC
To see all the columns in this table: