Más ciego que un topo

Pictures taken from Google Images, «Blind as a bat»
Click on the image to watch the video of the song, «Blind as a bat» in the Corpse of the Bride by Meatloaf

Meaning:

When someone is as blind as a bat, that person is not able to see anything at all, or at least that person has a very poor vision.

Pictures taken from Google Images, «Blind as a bat»
Click on the image to watch the video «Blind as a bat» in Smallville by Meatloaf

Origin:

There are many expressions that use analogies; as deaf as a doornail, as slow as a turtle, as sly as a fox. Bats are animals which can´t see anything at all. The way they guide themselves while flying is by sonar waves they shout out.

Pictures taken from Google Images, «Blind as a bat»
Click on the image to watch a video about echo location for blind bikers by HDNetworldReport

Example:

Ni un martillazo más / Es hora de echar la hamaca

Pictures taken from Google Images, «Call it a day»
Click on the image to watch the trailer of the movie, «The Night We Called it a Day»

Meaning:

This idiom means that it is time to stop work.

Pictures taken from Google Images, «Call it a day»
Click on the image to watch the video of the song «Call it a day» by Rachel Talbott

Origin:

People start the day working and spend most of the day working as well. Then, when we call it a day, we mean that it has been enough work for one day and it is time to go home to relax and to save energy for tomorrow´s workday. This idiom could have been coined in the XIX century when people devoted most of their to work.

Pictures taken from Google Images, «Call it a day»
Click on the image to watch the video fo «Call it a day promo Summer 2013» by Gucci Submarine

Example: