Can I open Excel .xlsx files with LibreOffice Calc?

My copy of LibreOffice, version 3.5.0rc3, is capable of opening and saving xlsx files. Presumably any version after that will, and probably some version before. LibreOffice has more community developed plugins in its package, so OpenOffice may not have xlsx capabilities.

Who knows if every weird format will work correctly either.

Ubuntu 12.10 has libreoffice 3.6.2, which really should have the support you need.

Install LibreOffice:

sudo apt-get update
sudo apt-get install libreoffice

You can try later versions of LibreOffice (3.6.2 is declared stable) and also the latest version of Apache OpenOffice, AOO 3.4.1.

If your colleagues are using the new version, Office 2013 Excel, the best route may be to have them save the documents as ODF for you.

Another alternative is to upload the .xslx files to SkyDrive by creating an account at http://skydrive.live.com. You can then view and edit them in a browser (Internet Explorer, Firefox, or Chrome). You don't need Microsoft Office installed. You'll be warned if a spreadsheet uses features not supported by the SkyDrive versioin.

In all cases, you will have to experiment to see which routes provide the greatest preservation of fidelity in the spreadsheets.

Your colleagues who have Microsoft Office can obtain them back directly from SkyDrive and also save them to SkyDrive from current versions of Office, if that makes it easier for you (and for all of you when not in the office). You'll probably want to create a folder in which only those live.com accounts that you give permission can see and/or edit the documents.

Try the latest version of LibreOffice (3.6.2). I had some trouble opening .xlsx files in the 3.5.X version, but it seems that they've fixed some bugs in the latest version :-)