Analyzing current activities of users in your SQL Server is mandatory task for monitoring your SQL Server performance can be queried for this purpose with little alterations. For example to get current activities for database we can run script like
select hostname, program_name, loginame, cpu, physical_io, memusage, login_time, last_batch, status from master.dbo.sysprocesses where dbid = db_id('AdventureWorks') order by hostname
Also a very efficient and informative system stored procedure is available to get same type of information. For example to get same information for our server instance
Above stored procedure will provide valuable information for all databases. So you may choose either way according to your requirement. By using custom script there is choice to implement sorting and customizing the out put columns number.