I'll see your Drupal and raise you one better: how about using Drupal/OpenAtrium?
You may recall the previous Presidential administration made headlines by replacing the Clinton administration's IBM/Lotus Notes Domino email/groupware servers with MicrosoftExchange (and presumably SharePoint also, but I'm not gonna go there).
The current Presidential administration of course had to ditch that Microsoft crap as fast as it possibly could. Obviously, continuing to use it would become a political and legal liability. They chose to use Drupal/OpenAtrium. Using OpenAtrium2 on Drupal 7, you too can enjoy a smartphone-enabled responsive intranet, with a minimum of development and budget.
FULL DISCLOSURE: I am a Drupal OpenAtrium developer (and am looking for my next project, so am available for private discussions). In fact at the same time it went public that The White House uses OpenAtrium for their project management and collaboration requirements, I delivered a similar collaborative project management intranet to NYSE Euronext. It was used by teams at the Amsterdam, Paris, and New York Exchanges while I was there. Before others also realized, I ascertained my assignment put my development efforts (and bug-tracking/feature requirements) in direct competition with Atlassian JIRA, so I took JIRA head-on. Just before Christmas a meeting was held, and I was told a Sr. VP at NYSE had decided my OpenAtrium development of a few weeks was superior and thus more desirable than JIRA, and I won(!) the competition. I was told then NYSE would use my OpenAtrium, and ditch JIRA, because my OpenAtrium Atrium development after only a few weeks could clearly beat JIRA requirement per requirement, while being much more user-friendly, and with a (dare I say) sexier GUI.
Alas, it was not to be (for me), and ultimately JIRA won, and I lost, and was soon out of a contract also. But still! I was a contender, dammit! All I got to work with was a bunch of Microsoft Office tools, Windows, and we were graced to also use FireFox. I delivered a Drupal application to NYSE overnight using my own VPS at Linode, with zero budget out of fear of job-loss. Previously, NYSE loved their 2-D spreadsheets and email, for project management. I requested early-on to be allowed to import their spreadsheets into a 3-D relational MySQL (drupal) database early on and was told "No". After several weeks passed, of no progress made by me to answer the report-requirements/questions posed of me by NYSE bean counters despite my best efforts with Microsoft Excel and %$#@! pivot tables, I asked my boss again, can I import the data into MySQL? I was then told yes, because that info was due weeks ago, was very late, and I was otherwise about to be fired. I worked all night and less than 24 hours later, all was imported into Drupal and I was able to report on and answer every question posed upon me. A week later, that Drupal database became a Drupal/IOpenAtrium intranet, and evolved into a very popular project management and collaborative tool. The #1 feature was: MULTITASKING. No longer did all my colleagues have to take turns updating the single spreadsheet, one at a time, with their totals at 5 o'clock, before they could go home! This was a huge hit from the staff. Meanwhile NY loved the spreadsheet import/export feature I implemented for them (HAD to have that to get approval). The Drupal (spreadsheet) sheetnode module is better (and sexier) than Google Docs IMHO. NYSE thought so too. For awhile there, I beat JIRA at NYSE using Opentrium, and I'm very proud of that.
FWIW, I have code for responsive video content-types about 85% finished, based upon the video.js open-source player.