If your theme does not have a 404 page template and you are too lazy to create your own creative 404 page, then you may want to consider using the Blue Screen of the Dead WordPress Plugin from KokaKiwi.
By installing the plugin on your website your visitors will get the famous blue screen of death whenever they enter an incorrect URL. The page includes a link to your sites home page.
It’s not the most practical solution for dealing with traffic to incorrect pages (a search box and archives link really helps), but it’s a good option for those who want something simple.
Blue Screen of the Dead can be downloaded from the link below.
Link: Blue Screen of the Dead
* Note: The plugin developers’ native tongue appears to be French. So I believe we should all excuse him from calling the plugin ‘Blue Screen of the Dead’ rather than ‘Blue Screen of Death’ :)